ci: define concurrency and job dependencies for our GH actions

.github/workflows/continuous-integration.yml

@@ -12,6 +12,12 @@ on:
     branches:
       - "main"
 
+# Cancels all previous workflow runs for the same branch that have not yet completed.
+concurrency:
+  # The concurrency group contains the workflow name and the branch name.
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 env:
   COMPOSER_ROOT_VERSION: "1.99.99"
 
@@ -66,6 +72,7 @@ jobs:
 
   security-analysis:
     name: "Security analysis"
+    needs: ["coding-standards", "static-analysis"]
     runs-on: "ubuntu-latest"
     steps:
       - name: "Checkout repository"
@@ -91,6 +98,7 @@ jobs:
 
   code-coverage:
     name: "Code coverage"
+    needs: ["coding-standards", "static-analysis"]
     runs-on: "ubuntu-latest"
     steps:
       - name: "Checkout repository"
@@ -115,6 +123,7 @@ jobs:
 
   unit-tests:
     name: "Unit tests"
+    needs: ["code-coverage", "security-analysis"]
     runs-on: ${{ matrix.operating-system }}
 
     strategy: